


A Soldier's Duty

by mindninjax



Category: Shingeki no Kyojin | Attack on Titan
Genre: Ambiguous/Open Ending, Angst, Commander kink, Daddy Kink, F/M, Pregnancy sex, Sex, Squirting, Unplanned Pregnancy, Vaginal Sex
Language: English
Status: Completed
Published: 2021-02-18
Updated: 2021-02-18
Packaged: 2021-03-14 00:47:21
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,850
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29534961
Author URL: https://archiveofourown.org/users/mindninjax/pseuds/mindninjax
Summary: How dedicated to the cause is the Commander? You intend to find out.
Relationships: Erwin Smith/Reader
Comments: 7
Kudos: 118





	1. Chapter 1

**Author's Note:**

> Hey did you know that I would like to be pregnant with Erwin Smith's child? If you're the same, can we be best buds?

Erwin scribbles on the paperwork in front of him, the candle beside him spilling wax onto the dark wooden desk. It’s late and he’s been working diligently through the night, filling out reports to inform the higher ups of the recent failure of the 57th Reconnaissance Mission. Frustration seeps out onto the page as his quill presses deeply into the parchment, leaving scattered dark imprints. 

He’s familiar with failure, has tried many times not to let it get to him but sometimes, in the dark of night when everyone is asleep he lets loose. The commander can’t always be as calm, cool, and collected as he is in front of the other soldiers. They had been so close, had the female titan in custody, but whoever the enemy is, always seemed to be one step ahead. 

The quill snaps from the pressure of his large hands pressing into the parchment angrily. “Shit,” he mumbles under his breath as two tiny raps on his office door draw his attention. 

“Yes, what is it?” he says as his icy blue eyes fall on the door. 

He immediately calms when he realizes it’s just you. Aside from Levi, he’s always felt he can be the most relaxed and himself around you, dropping the strong façade of “The Commander of the Scouts”.

Your hair is down, not in its usual sleek up do and your shirt is untucked with a few loose buttons. Your demeanor is relaxed as you stroll into the office. An expression Erwin can’t quite put his finger on dawns your face. 

“I knew you’d still be awake, you’re starting to get as bad as Levi,” you sigh shaking your head and scolding him. Despite being ranked underneath him, he always feels a bit of shame when you scold him for not taking care of himself. Your eyes fall to the page he’s been scribbling on and the broken quill in his fingers and you walk over to take it from his hands and wipe the ink with your handkerchief. 

“I swear the two of you, will be the death of me,” you say focusing on the ink between his fingers. “Failure doesn’t mean defeat, ya know. It just means you approach the issue from a new angle.” You finish and put the handkerchief back into your pocket. 

It hasn’t been difficult to uphold the relationship of commander and subordinate between the two of you, but Erwin will admit it's times like this where the line becomes more blurred. It’s how the first time, _the first mistake_ , happened. And after, you’d felt so good in his arms that he’d let it continue. 

He likes keeping you close, like his security blanket and heaven knows he deserved a bit of joy in his life. Which is why you didn’t mind his rule of “no attachments”. The few times he's called you to his office after a stressful mission made you feel responsible for him in a way. You’d be lying if you said you didn’t enjoy how he’d ripped off your clothes and kissed you passionately or how you could feel his neediness to be warm and safe inside you. 

He gazes at you, a wrinkle in his forehead as you read his thoughts of irritation. You playfully place your index finger on the wrinkle and say “Stop that, or it’ll be permanent and everyone will be afraid of you like they are of Levi.” 

He smiles then, relaxing a bit more at your simple touch. He wonders why you’re here, a night cap perhaps? He could use it given the circumstances, plus you do look lovely in this lighting. 

“What is it, y/n? What’s bothering you?” He mutters as he runs a large hand up your thigh. You place your hand over his and stop his movement, squeezing gently. 

“I have a question for you Commander.” 

He stares at you intently, a slight rustle in his pants as his title falls from your pretty lips. He’s a bit thrown off, you don’t usually refer to him as such unless you’re both on duty or when he’s pounding into you relentlessly. 

“Yes?” 

“Have you ever thought about having a family?” You ask him seriously. His heart skips a beat. Why would you be asking this? You two had been careful, right? He made sure of it, with perfect accuracy. You can see his mind racing and immediately tack on “It’s just a question Erwin, not a math problem.” 

The assurance in your voice calms him a bit and he opens his mouth to say “No” before shutting it again. He contemplates lying to you but decides against it. 

“Yes. A while ago...with Marie,” he responds. You nod remembering when he told you about her, the only woman he’d ever been in love with. He shuffles nervously, watching your pensive expression. “Have you?” 

You walk to the window in his office to gaze out dreamily. “Of course. Many times actually. There have been times when I’ve thought to myself ‘I’ve seen enough of this nightmare’, and I plan to sneak out of here, find a nice strong husband who will love me forever, have a few kids and live out the rest of my life oblivious and safe behind the walls.” 

Erwin stands and joins you at the window, frowning slightly. Not realizing the jealousy he feels at the mention of this made up husband, he says in a gruff voice that is reminiscent of him scolding a soldier “Is this your way of saying you’re planning to abandon your duties as a scout? You know the penalty is death.” 

You chuckle, ever aware of his hidden feelings and picking up on the jealousy in his tone. “You’re always _The Commander_ first, comrade second. Haha don’t worry I understand,” you chuckle again not looking at him. He still stares at you, trying to gauge what you’re thinking and that weird expression that is still on your face. 

“I think about running away and starting my little family, but I know I can’t be oblivious. I know that after what I’ve witnessed, every time I shut my eyes to sleep next to my 'would be' husband, all I would see was our beautiful little children. Their eyes would look into mine, terrified and helpless as they slid down the putrid gullet of a titan. The last thing they would think was why their mother failed them, and the last thing I would think was that I should’ve never run away and they should’ve never been born,” you say not realizing the moisture falling from your eyes.

Erwin reaches out to stroke your cheek but you recoil from his touch. He’s confused and arches an eyebrow as you finally turn to look him in the eyes.

“You would charge a deserter with treason and have them executed, even after knowing the horrors of what we see everyday?” you ask him seriously. 

He nods morosely. “It’s my duty as Commander of the Survey Corp,” he responds plainly. 

You turn back to the window smiling to yourself sullenly. “I thought you’d say that,” you mumble quietly to yourself. 

“I have one more question before you retire for the night Commander,” you sigh and turn back to stare intensely into his clear blue eyes. 

“Would you charge a deserter with treason and have them executed, if they were pregnant with your unborn child?” 

–


	2. Chapter 2

**Summary for the Chapter:**

> How will Erwin respond to your question?

**Notes for the Chapter:**

> This one is SPICY and also angsty. Get ready!

_Would you charge a deserter with treason and have them executed, if they were pregnant with your unborn child?_

The room is silent. You can _hear_ Erwin’s heart drop and the lump in his throat be swallowed as he processes your words. He gawks a crystal blue stare at you, blinking rapidly. His mind is always moving so fast, you can tell he’s weighing his options, trying to figure out what to say to you. 

The anxiety you had before telling him vanishes. You accept your fate, your _mistake._ In your eyes, there’s nothing but clarity and acceptance but it blocks the cursed hope hidden away as well. He frequently takes the blame for all the scouts, perhaps you can do him this one favor and take the responsibility from him. 

The crackling of the fireplace tucked away in the corner sounds louder than usual. The smack of his lips as his tongue runs over them is too loud and you’re wishing he would just _say_ something. You don’t break eye contact and hold your breath as he opens his mouth then closes it again. 

He repeats the motion multiple times before he finally mutters in a voice full of sarcasm, “Is this still a hypothetical question?” 

You laugh, hunch over holding your stomach as a hearty gut wrenching guffaw wracks your body. You can’t control it. It’s a mix of relief and the escape of the anxiety you thought had disappeared. He moves closer to you, reaching out another hand to caress you hesitantly. 

His warm touch instantly soothes you as you meet his gaze and stand back up straight. There are little tears at the corner of your eyes, and Erwin reaches down to pluck them from the little wisps of eyelashes gathered there. You close your eyes and lean in, anticipating his rough hands. 

Before his fingers brush against your skin, he’s gone from in front of you. You open your eyes to see him walking toward the door and your heart sinks. You suppose it’s fair. It’s a lot to deal with, especially for the commander who holds humanity’s well being on his shoulders. You didn’t think he would sweep you off his feet, marry you, and buy you a house in the country, but the initial affection and abrupt pull away from you has left you broken. 

You bite your lip as you move to the window to press your head against the cool glass. The moon shines through, reflecting its pale creamy glow onto you. Your hand reaches down to cradle your stomach, a very small bump making its presence known. You let the tears flow as you take a deep breath. His rejection at least meant you're safe to leave tonight. There’s no way you could stay here, and if you left now, you’d be able to put good distance between here before Scouts were sent out to look for deserters. 

Your heart races and you take deep breaths as you try to calm yourself. You’ve come to your conclusion in a matter of seconds, and although it pains you, you know what has to be done. You give one big sigh again before turning around and running face first into Erwin’s broad chest. A surprised gasp escapes you as you look back up to him. 

His bolo tie is loosened, he’s taken off the brown jacket and unbuttoned the top two buttons of his pressed white collar shirt. His shirt is untucked and the sleeves rolled up to show his forearm. Little blonde hairs cover his arms and hide the faint veins that peruse up his bulging, muscular arms. He stares at you again, the serious “Commander” face he wears for everyone else paints his features. It makes you wince; he’s never shown you that face during the intimate moments the two of you share. He puts a long finger underneath your chin and tilts your head up to gaze deeply into your eyes. 

“Are you-”

“Yes,” you say to stop him from saying the word. He frowns at you and you drop your head. He jerks it back up to his gaze and holds your face not allowing you to turn from him again. 

“I want to hear you say it,” he says in the “Commander” voice. He melts you, forces you to comply almost automatically and makes your already damp undergarments even wetter. 

“I am pregnant, Erwin. You will be a father.” 

You bite your lip as the room becomes quiet again. He stares in bewilderment first at your face, full of tears as they fall down your puffy cheeks, and then down to your belly. His finger moves over your lips, pulling them from your teeth and opening them slightly before he brings his face down to yours and kisses you. He slips his tongue between your lips and pushes past your teeth to taste you. 

His kiss deepens as it continues and soon both of your eyes are closed and your arms are reaching up to wrap around his neck. Your fingers run through his hair and he groans, pulling you in closer to his body. Your tongues dance and swirl like a couple performing an enchanting waltz in the middle of the ballroom. He places a hand on your ass and squeezes as he continues to kiss you. He leads you both over to the heavy wooden desk in the middle of the office until your ass hits the edge. 

When the two of you break to catch your breath, you are panting. He lifts you and sits you on the desk. His hand moves your hair from your face and you lean into it again, relishing in the feel of his rough fingers. Your panicked eyes shoot open and scan to find the door, wanting your secret relationship to stay under wraps. You relax a bit when you find that it is shut tight and realize, that’s why he walked away. 

His eyes roll over your body and stop at your stomach. He places a large hand over your womb and rubs the tiny protruding bump over the thin shirt you’re wearing. 

“Beautiful,” he mutters as the hard serious expression he wore is replaced with adoration. His words tear into your heart, barge in like a thief in the night and settle there. You try to push it out, forget this look on his face. It’ll only make it harder, only bring pain to the both of you. You make the hard decisions here, you shoulder the burden so he doesn’t have to. It’s why this arrangement started in the first place, right? There’s no way this can end with the two of you happily raising a child.

Humanity _needs_ him. 

“Erwin you can’t-”

“Shh...honey, it’s ok,” he says, kissing your lips softly before bending down in front of you and lifting your shirt. He kisses your belly and you gasp at how soft and cold his lips are against your skin. Your hand flies to his head as he peppers kisses all over your stomach and mutters things you can’t make out. He’s never called you “honey” before and it worries you only a little. 

What is he doing? Why is he indulging you? Is he trying to trick you? You of all people know how Erwin’s mind works, how he’s able to get whatever he wants just by using his words. How great his coercion skills are. What if he stops you from leaving? Your heart and mind race and you close your eyes and try but fail to push him away. It hurts to think about, pushing him away and leaving to have his child away in the country without him. 

“Please, don’t leave,” he whispers against your stomach. Your eyes shoot open again and look down at him. His eyes are closed as he trails his nose across your bump. It makes sense then: a distraction, like you’ve always been. It’s always been why you visited him. No strings attached. The pact between you two. 

If you can give him anything, you can give him tonight.

Your fingers reach down to grab his face and bring it back up to your lips. “Kiss me,” you whisper breathlessly before hungrily pressing your lips back to his. He takes control then, unbuttoning your shirt with expert fingers and running his hands down your arms. 

He can see the tells of pregnancy now that you’re exposed to him, the swell of your breast, your darkening areolas, the way your curves dig deeper and become more voluptuous. Your fertility is beautiful, welcoming, _primal_ and although Erwin knows that you’re in this state _because_ of him, he can’t help but want to fill you up again and cement the fact. 

His fingers brush as lightly as they can over your raised nipple and you twitch excitedly and whimper as he teases you. You feel him grow hard against your leg. Your pleading whimpers drive his determination and all he wants to do is make you feel good. He latches to your breast licking and sucking your nipple. His hand grasps it and he revels in how much it fills his palm. You moan, every sensation of his tongue and hands send tingles down your spine. He’s always been adept at sex, very attentive to your body and what you like. He likes pleasing you and seeing you wriggle for him, beg for him as you do now. 

“Please Erwin, I..” you moan out. You can’t believe how aroused you are, even his scent excites you and makes you dribble for him. 

“That’s not what you call me,” he says as he moves farther down your body to undo your pants and pull them down your thighs. You squeeze your eyes shut as his hands run up and down your thighs. 

“Ah..ah…Commander,” you stumble out and his eyes get the familiar aroused glow before a hint of disappointment flashes in his oceanic eyes. 

The wet mark on your undergarments makes his eyes widen and his mouth water. He pulls back from you to get a good look, marveling at his prize and giving a satisfied yet possessive grin. You’re _his_ and he likes it. His fingers run over your clothed clit and you almost come immediately from his touch.

“So wet already honey, I could get used to this,” he says as he pushes the cloth to the side and plunges two finger into your hot sex. You lurch as he enters you, head falling back and moaning louder than you ever have during the many nights the Commander has taken you. You tremble as he wiggles his fingers slightly and pulls them out, letting a long trail of juices follow as he exits. 

“ _Shit,_ is this all because of the baby?”

You moan at his words as you watch him slip the two fingers into his mouth and groan at your tangy flavor. When he refers to the bump as a baby it awakens something in you and all you want is to feel him inside you. You whimper and beg in a pitiful little voice.

“Please, Commander. Fuck me,” you plead. He unbuttons his pants, eyes on yours now as he pulls them down past his thick thighs. He tears off your underwear and rubs his head over your slippery folds, using your immoderate slick to ready himself. 

“I will honey, but only if you call me the right thing,” he says as he lightly taps his thick cock on your quivering clit. Your mind is hazed with pleasure and you wrack your brain for what he could possibly mean. “Commander” has always been what you call him, has always been the name that makes him fuck you harder. That is until…

“Please, please _daddy_. Fuck me.”

He enters you as the last syllable tumbles from your lips. You lay back flat on the desk, knocking all of the papers and the heavy candle holder onto the floor with a crash. Your hands desperately reach out for something to hold as he plunges deeper into you, the tip of his cock tickling your cervix. 

It’s the first time Erwin is _noisy_ while fucking you. He groans loudly when he bottoms out, feeling how tight your walls constrict around him. The lewd squelch of your pussy is music to his ears as he sets a pace to fuck into you. He wraps your legs around his waist and holds your hips, drilling and grinding into you.

It doesn’t take long before you are gasping and scratching at the wood of the desk as your orgasm rips through you. You arch your back up, screaming Erwin’s name as he thrusts into you and stays, waiting for you to come down from your high. When you’ve relaxed and caught your breath he starts moving again and your eyes shoot open. 

“I know you’ve got another one in there for Daddy,” he says grunting as he moves his hips and unbuttons the rest of the buttons on his shirt. You can see the sweat dripping down his abs and you desperately want to lick them amazed at how you’re already ready to go again. He sets a steady pace again, leaning over you to kiss your lips and breath heavily against your neck. 

Your moans turn to whimpers again as the pressure builds inside you. He mutters against your neck, and you’re only able to make out a few of the things he’s saying. 

“…wanna fill you up honey…know you’re mine.. I’ll be a daddy.” His deep voice rumbles against your frame as his hand snakes down to play with your clit. His thrusts get sloppier, more intense and the slap of his balls on your ass speeds up.

The desk moves with every drive of his body against yours and you feel yourself plunge over the edge as you squirt all over Erwin’s cock. You cry out but there’s no sound when you feel him pound into you a final time and spurt cum into your gracious pussy. 

He pants as he falls on top of you and your arms wrap around his broad shoulders and back. Your legs are quivering but neither of you move from your position. You run your fingers through his hair as you stare up at the ceiling. He places his ear to your heart as he closes his eyes to listen to it’s thrumming melody and dream of hearing his child’s one day. 

“Stay,” he says putting his arms underneath your torso to hold you close. He doesn’t see the tears pooling in your eyes nor does he see you shake your head before you respond. 

“Ok.”

-

The next morning is a blur. There’s a meeting with the Premier to discuss Eren’s custody and Erwin has to ride into Stohess in a few days. He wants to meet with his commanding officers to discuss but he can’t help but be distracted by thoughts of you.

He’d walked you back to your room, telling you to get rest and assuring you that you’d discuss more about your situation in the morning. You’d agreed, looked into his eyes with the loveable doe-eyed expression of trust he’d come to secretly adore and bid him good night. 

As he enters the council room, Hange and the others look worried and confused. Levi’s normally stoic manner is decorated with a hint of concern and frustration. Erwin stirs, very seldom does Levi express unease this clearly in his expression. Something must be extremely wrong.

“What is it, Levi?” Erwin asks, catching the Captain’s eye.

“Y/n is gone.”

\--

**Notes for the Chapter:**

> I am once again here to say I would love to have beautiful passionate sex with Erwin while already being pregnant with his baby.


End file.
